The present invention is related to a centrifugal fan, and more particularly to a centrifugal fan mounted in a laptop computer.
In the modern era, the computer has become an indispensable tool for the people in their daily lives. The market of the laptop computer has rapidly expanded, together with the rise of the living standard and with the rise in living standard and with the demands of business. In recent years, the major manufacturers of laptop computers have dedicated money and manpower to research and development the laptop computer to increase. One bottleneck imposed on the development of the laptop computer is the issue of the heat dissipation. The key feature of the laptop computer is that the user can carry it and use it at anytime, usually by placing it on the lap for operation. If the laptop computer becomes overheated in such situations, it will not be usable and it will also be inconvenient to transport. Thus, the key feature of the laptop computer will be degraded.
Most of the current laptop computers use a fan to dissipate the heat generated in the laptop computer. The heat generated in a laptop computer is expelled out of the laptop computer by way of air convection. The fan expels the hot air out of the laptop computer and draws the cooling air into the laptop computer for lowering the temperature of the a laptop computer. Because the laptop computer must be small and thin for portability, it is somewhat difficult to incorporate a fan inside the laptop computer. If a common axial flow fan is adopted for dissipating the heat generated in a laptop computer, the airflow will not be smooth and the heat-dissipation efficiency will be low owing to the forced air convection induced by the axial flow fan. If a centrifugal fan is adopted to dissipate the heat generated in a laptop computer, the centrifugal fan is able to match the natural fundamentals of airflow and thus is feasible for dissipating the heat generated in a laptop computer.
Please refer to FIG. 1 which is the top view of the conventional centrifugal fan. An outlet opening is located on the side of the casing 11, which is not shown in the drawing. It can be seen from FIG. 1 that an impeller 13 facing the intake opening of the casing 11 (not shown) is rotatably mounted in the casing 11, and the fan blades 12 are attached to the impeller 13. The cooling air will flow into the intake opening by means of the rotation of the impeller 13 as well as the fan blades 12 and then blow off through the outlet opening on the side of the casing 11.
While the centrifugal fan is operating, noise will be inevitably generated as long as the air is flowing inside the centrifugal fan. Moreover, the faster the fan rotates, the louder noise will be generated. Therefore, if one desires to increase the rotating speed of the centrifugal fan in order to improve the heat-dissipating efficiency, the noise will become louder as well.
Accordingly, it is desirable to modify the centrifugal fan to solve the dilemma of whether to improve the heat-dissipating efficiency or to lower the noise.
It is an object of the present invention to provide a centrifugal fan with an increased air capacity and a lower noise.
It is another object of the present invention to provide a centrifugal fan with an improved heat-dissipating efficiency.
The centrifugal fan of the present invention includes a casing having an intake opening and a horn-shaped outlet opening for increasing the air outflow, an impeller rotatably mounted in the casing with a reduced diameter and bared inner space for increasing the air capacity, and fan blades attached to the impeller, wherein each of the fan blades is chipped at the rim for lowering the noise.
In accordance with the present invention, the fan blades are protruded from the rim of the impeller.
In accordance with the present invention, the gap of the fan blade is near the intake opening of the casing.
In accordance with the present invention, the inner periphery of the horn-shaped outlet opening will be reduced toward the inner space of the casing.
Now the foregoing and other features of the present invention may best be understood through the following descriptions with reference to the accompanying drawings, in which: